Revolving Flat

ABSTRACT

A method for fastening a clothing strip ( 10 ) to a card-flat bar ( 21, 31 ) by a fastening means in the form of clips ( 25, 35 ) is presented. In this case, the clips ( 5, 25, 35 ) are integrally formed onto the card-flat foot ( 23, 33 ) by press rams ( 12 ) guided simultaneously from both sides of the card-flat bar ( 21, 31 ) and parallel to the plane of the clothing strip ( 10 ). The clip ( 25, 35 ) integrally formed onto the card-flat foot ( 23, 33 ) loops around the latter with a looping angle (α) of less than 90° and more than 30° (degrees of angle). A corresponding tool for carrying out the method and also a revolving card flat are likewise proposed.

The invention relates to a revolving card flat with a card-flat barwhich has a card-flat foot and a web lying above the card-flat foot, andwith a flexible clothing in the form of a clothing strip and with atleast one fastening element in the form of a clip, the clip beingattached with a first portion to the clothing strip, being led with asecond portion along one longitudinal side of the card-flat bar andpartially looping with a third portion around the card-flat foot with alooping angle. The looping angle is defined as the angle between theperpendicular, touching the side face of the card-flat foot, to theclothing bearing face of the card-flat foot and that face of thecard-flat foot onto which the third portion of the clip is integrallyformed.

Various types of construction of revolving card flats are known from theprior art. Revolving card flats are used in carding. The revolving cardflats employed nowadays consist essentially of a card-flat bar with aclothing. The card-flat bar is composed of a card-flat foot and of a weblying above the latter. The clothing is fastened to the card-flat footwith the aid of clips. The clothing itself is used in the form ofclothing strips, on the underside of which a multiplicity of clothingneedles in the form of small wire hooks are fastened. At the two ends ofa card-flat bar, devices are provided which make it possible to fastenthe card-flat bar to a chain or a belt.

U.S. Pat. No. 581,749 discloses a revolving card flat and acorresponding tool for fastening the clothing strip to the card-flatfoot. In this case, first, the clips are connected to the clothingstrip. In a further step, the clothing strip thus prepared is joinedtogether with the card-flat bar, and subsequently the free portions ofthe clips are bent around the card-flat foot, so that the clothing stripcomes to lie, free of play, on the card-flat foot. The card-flat foot isin this case surrounded by the clips in a bracket-like manner. To makethis connection between the card-flat foot and clothing strip by meansof clips, a complicated movement of the too used is necessary.

DE 128 552 likewise discloses the fastening of a flexible clothing inthe form of a clothing strip to the card-flat foot of a card-flat bar.The clip used in this case, on the one hand, engages into the foundationof the clothing strip and, on the other hand, engages around orsurrounds the card-flat foot. This makes it possible for the liningmaterial of the foundation of the clothing strip to lie firmly on thecard-flat foot. Here, too, the disadvantage is that clips bent on bothsides have to be manufactured.

FIG. 1 shows a device, such as is used for drawing clothing strips ontocard-flat bars. The card-flat bar 1 is built onto a clothing strip 10previously laid into a holding device 8, so that the card-flat foot 3comes to lie on the clothing strip. The clips 5 are already fastened tothe clothing strip 10 on longitudinal sides of the latter. The card-flatbar 1 is consequently introduced with the card-flat foot 3 between theclips 5. With the aid of prebending rollers 6, the clips 5 arepreformed. In a second step, by means of the form rollers 7, the clips 5are integrally formed onto the card-flat foot 3. The prebending rollers6 and form rollers 7 are moved in the longitudinal direction of thecard-flat bar 1 for the integral formation of the clips 5, while therollers rotate and are pressed against the card-flat foot 3. The deviceshown has the disadvantage that only a specific shape of the card-flatfoot 3 fits together with the predetermined form rollers 7. Also,complicated movement and clamping mechanisms are necessary so that theoperation described above can be carried out.

WO 2006/039829 discloses a further example of a device for attaching aclothing strip to a card-flat bar. A prepared clothing strip, in whichthe clips are already fastened with a first portion on both sides, isintroduced into the device. The card-flat bar is subsequentlyintroduced, with the card-flat foot against the clothing strip, into thedevice, so that the clips lead with a second portion along thelongitudinal sides of the card-flat foot. The bending cheeks of thedevice are then pivoted inwards against the card-flat bar, with theresult that the third portion of the clips is integrally formed onto thecard-flat foot. To generate the necessary holding force, in addition, adeformation of the clips along the longitudinal sides of the card-flatfoot is generated by means of press battens. One disadvantage of thedevice is that a plurality of movements of pressing tools and bendingcheeks are necessary in order to achieve a fastening of the clothing tothe card-flat bar. Also, there is the risk that, in the case ofexcessive deformation of the clip, a change in shape of the overallcard-flat bar may occur, because various elements of the card-flat footare spanned by the clips.

The prior art for fastening clothing strips to card-flat bars with theaid of clips likewise entails the disadvantage that the card-flat foothas to be subjected over its entire length and width and also its heightto a narrow manufacturing and dimensional tolerances. In order toachieve a reliable fastening of the clothing strips, an exactco-ordination of the pressing tool, form rollers and dimensions andshape of the card-flat foot with the dimensions of the clips and theirmaterial properties is necessary. This leads to a cost-intensiveproduction of the individual parts and also of the equipment necessaryfor assembling them.

The object of the present invention, then, is to avoid the disadvantagesof the prior art and to provide a simple connection between thecard-flat foot and clothing, without having to allow for any loss ofholding force.

The object is achieved by means of the type of construction of arevolving card flat of the type mentioned in the introduction and bymeans of the method and the tool necessary for this, having thecharacterizing features of the independent claims 1, 6 and 10. Theobject is achieved in that the clip loops with a third portion aroundthe card-flat foot with an angle of between 90° and 30° (degrees ofangle).

A revolving card flat according to the invention has a card-flat bar.The card-flat bar is composed of the card-flat foot and of a web lyingabove the card-flat foot. Card-flat bars are nowadays produced mostly inone piece from steel or cast iron and also in the form of hollowprofiles consisting of light metal or light metal alloys. Card-flat barsconsisting of plastic or of composite materials may also be envisaged. Aclothing is attached to that side of the card-flat foot which liesopposite the web, the clothing bearing face of the card-flat bar. Inthis case, mostly, flexible clothings are used. A flexible clothingcomprises a foundation which is constructed from a plurality of fabriclayers and which is pierced by needles. The clothing is produced in theform of strips, the width and length of these clothing stripscorresponding to the dimensions of the card-flat foot. The clothingstrips and the card-flat foot are held together along the longitudinalsides of the card-flat foot with the aid of fastening elements, what areknown as clips. The clips have a first portion which is connected to theclothing strip. This takes place mostly by pricking into the foundationand by subsequently bending round the clips, so that a second portion ofthe clips leads along the lateral longitudinal edges of the clothingstrip, parallel to the side faces of the latter or the longitudinaledges of the card-flat foot, in the direction of the web. A thirdportion of the clips then projects away from the clothing strip beyondthe card-flat foot.

There has previously been the conviction that a sufficiently highholding force for operational requirements between the card-flat footand the clothing strip can be achieved only by a crimping of the clip.This meant bending the third portion of the clip around through morethan 90°, thus resulting in a looping around of the card-flat foot ofmore than 90°. Bending around resulted in a bracketing of the card-flatfoot, which was intended to prevent the clip from slipping offlaterally. According to the invention, however, by the clip beingintegrally formed onto the contour of the card-flat foot, a holdingforce sufficient for the requirements can be achieved even in a case ofa looping around of less than 90°. Fastening the clothing stripsimultaneously from both sides gives rise in the clothing strip to atension which assists the frictional connection achieved by the clipfitting snugly against the card-flat foot. The frictional connection isachieved by the card-flat foot being looped around by the third portionof the clip. In this case, it was shown that a looping around of lessthan 90° leads, between the card-flat foot and the clip, to a frictionalconnection which fulfils the requirements to be met during operation bythe connection of the card-flat foot and clothing strip. As regards theproduction and releasability of the connection, a looping angle of lessthan 70°, in particular of 60°, proved to be advantageous. In order toobtain a sufficiently high holding force via the frictional connection,a looping angle of more than 30°, preferably of more than 50°, isadvantageous.

In a preferred version of the invention, the clip is manufactured fromlight metal or a light metal alloy. The necessary forces for integrallyforming the clip onto the card-flat bar are thereby reduced. Inparticular, the use of clips consisting of aluminium or of an aluminiumalloy has proved appropriate. The card-flat bars, too, may be producedfrom light metal or a light metal alloy. In particular, the card-flatbars may be designed as hollow profiles. The use of aluminium or of analuminium alloy is also advantageous.

The method for integrally forming the clips onto the card-flat foot ischaracterized by the use of simple press rams. The press rams in thiscase act simultaneously from both sides of the card-flat bar on theclips to be integrally formed. The press rams are in this case to bemoved towards one another transversely to the longitudinal direction ofthe card-flat bar. The movement of the press rams takes place linearlyin a plane which is parallel to the plane of the clothing strip. Thepress rams may be provided with a drive. The drive may take placeelectrically, pneumatically or hydraulically. A purely mechanical drivewhich can be actuated by hand may also be envisaged.

In a preferred version, the card-flat bar has above the card-flat footan additional rib which leads along, parallel to the card-flat foot,over the length of the card-flat bar. The rib in this case forms,together with the card-flat foot, a guide for the press rams. The pressrams are guided by this rib in their movement in such a way that theycannot avoid the clip.

The press rams are preferably manufactured from an elastic material,preferably from a thermoplastic, in particular polyethylene orpolyamide. As a result, that part of the press ram which slides along onthe card-flat foot and the third portion of the clip is deformed. Owingto this deformation, the press ram adapts to the contour of the clip andof the card-flat foot, thus leading to the clip being integrally formedonto the card-flat foot. By the clip being integrally formed exactlyonto the contour of the card-flat foot in this way, unevenesses in thecard-flat foot can be compensated. A compensation of production ordimensional tolerances on the card-flat bar is also possible. Alreadyused and therefore slightly damaged card-flat bars may be reequippedwith a clothing strip by means of the proposed method. When the pressingoperation has ended, the rams are retracted and resume their originalshape.

The tool used for carrying out the method makes it possible to receive acard-flat bar. The clothing strip, together with the clips alreadyfastened to it, and the card-flat bar are introduced into the tool. Theclothing strip and the card-flat bar are subsequently retained in theirposition with respect to one another. For this purpose, means areprovided which, on the one hand, make it possible to position theclothing strip and card-flat bar, for example guides, and, on the otherhand, fix this position, for example cramp it or clamp it.Advantageously, the card-flat bar is attained during the followingpressing operation by means of a holding-down device. The press ramsmoving forwards simultaneously from both sides may be manufactured inone piece and extend over the entire length of the clothing strip to befastened. A division of the press ram into individual segments may alsobe envisaged, in which case the drive for the press ram may likewise beapportioned to individual segments.

The invention is explained in more detail below with reference toexemplary embodiments and by means of drawings in which:

FIG. 1: shows a diagrammatic illustration of a device for assembly of acard-flat bar and clothing according to the prior art;

FIG. 2: shows a diagrammatic illustration of a cross section of a firstrevolving card flat according to the invention;

FIG. 3: shows a diagrammatic illustration of a cross section of a secondrevolving card flat according to the invention;

FIG. 4: shows a view of a detail of the fastening of a clothing strip tothe card-flat foot;

FIG. 5: shows a diagrammatic illustration of the tool for producing arevolving card flat according to the invention;

FIG. 6: shows a diagrammatic illustration of a cross section of arevolving card flat according to the invention during a pressingoperation.

FIG. 1 shows an arrangement, conventional according to the present-dayprior art, of a device for assembly of a card-flat bar and clothingstrip to form a revolving card flat. The figure was discussed in detailunder the prior art, and therefore a further description is dispensedwith at this juncture.

FIG. 2 shows a cross section of a revolving card flat according to theinvention. The clothing strip 10 consists of the foundation 9 and of theneedles 4 which are held in the latter and which constitute the actualclothing. The clothing strip is held on the card-flat foot 23 on each ofthe two sides by means of a clip 25. The card-flat foot 23 and the web22 located above it form the card-flat bar 21. This card-flat bar 21 isprovided (not illustrated) at its outer ends with a card-flat end headin each case.

FIG. 3 shows a cross section of a further revolving card flat accordingto the invention. The card-flat bar 31 is designed as a hollow profile,the hollow profile increasing in width towards the clothing strip 10 andforming the web 32. A card-flat foot 33 is formed at the lower end ofthe hollow profile. The slender part of the hollow profile in this caseforms the web 32. A rib 11 is integrally formed on the web 32 on bothsides above the card-flat foot 33 and runs over the entire length of thecard-flat bar 31. A clothing strip 10 is attached on that side of thecard-flat foot 33 which lies opposite the web 32, the clothing bearingface. The clothing strip 10 is held on the card-flat foot 33 by means ofclips 35 attached to the longitudinal sides of the card-flat bar 31.

FIG. 4 shows a view of a detail from FIG. 3. The clothing strip 10consisting of the foundation 9 and of the clothing 4 is fastened to thecard-flat foot 33 by means of the clip 35. The web 32 is laid, oppositethe clothing strip 10, against the card-flat foot 33. The card-flat bar31 is produced in one piece, so that the card-flat foot 33 and the web32 merge one into the other without any visible parting line. The clip35 is illustrated, laid out, in a side view in the further part of FIG.4. In this case, the region A constitutes a first portion of the clip35. This is provided at the outer margin with serrations which, in thefastened state, engage into the foundation 9 of the clothing strip 10.The region B designates a second portion of the clip 35 which, in theinstalled state, is led along the longitudinal side of the clothingstrip or of the card-flat foot. The region C constitutes a third portionof the clip 35. This is integrally formed onto the card-flat foot 33 andloops around the latter at the angle α. The looping angle α is definedas the angle between the perpendicular, touching the side face of thecard-flat foot 33, to the clothing bearing face of the card-flat foot 33and that face of the card-flat foot 33 onto which the third portion(region C) of the clip 35 is integrally formed. The third portion(region C) of the clip 35 is bent away at the looping angle α out ofalignment with the second portion (region B) of the clip 35, so thatthis third portion (region C) bears against the card-flat foot 33.

FIG. 5 shows diagrammatically the tool for fastening the clothing strip10 to the card-flat bar 21, 31. The half, designated by L, of FIG. 5illustrates a card-flat bar 21 according to FIG. 2. The half, designatedby R, of FIG. 5 illustrates a card-flat bar 31 according to FIG. 3.Irrespective of the differences between the two card-flat bars 21, 31,the procedure is the same for fastening the clothing strips 10 to thecard-flat bars 21, 31 or card-flat feet 23, 33. The clothing strip 10 isintroduced into a receptacle 14 in the tool. In this case, a depressionis arranged centrally in the receptacle 14 over the length of thecard-flat bar 21, 31, so that the clothing strip 10 is not damagedduring the fastening operation. The clips 25, 35 have in this casealready been attached to the clothing strips 10 beforehand. The regionsB and C of the clips 25, 35 are located in a plane which runs (notillustrated) advantageously perpendicularly to the foundation 9. Thecard-flat bar 21, 31 is introduced from above between the regions B andC of the clips 25, 35 (see FIG. 4). By means of a holding-down device13, the card-flat bar 21, 31, together with the clothing strip 10 lyingbeneath it, is pressed against the receptacle 14 and thus fixed. Thecard-flat bar 21, 31 and clothing strip 10 are thus tension-mountedbetween the receptacle 14 and the holding-down device 13 engaging on theweb 23, 33.

In a next step, the two press rams 12 are led simultaneously up to thecard-flat bar 21, 31 from both sides of the latter. The press ram 12presses the third portion (region C) of the clip 25, 35 against thecard-flat foot 23, 33 upon further movement. As a result, the thirdportion of the clip 25, 35 is integrally formed onto the card-flat foot23, 33 by the press ram 12. The press ram 12 is preferably manufacturedfrom an elastic material, so that it slides over the third portion ofthe clip 25, 35, while the press ram 12 adapts to the contour of thecard-flat foot 23, 33. As a result of this type of “bending” of thethird portion of the clip 25, 35, the second portion of the clip 25, 35is drawn upwards against the ram 12. Since this effect occurs on bothsides of the card-flat foot 23, 33, the clothing strip 10 is drawn apartand tensioned.

In the half, designated by R, of FIG. 5, in a preferred version of theinvention, the rib 11 is formed above the card-flat foot 33. The rib 11is shaped in such a way that its inclination gives rise to a preferablysymmetrical depression between the rib 11 and the card-flat foot 33,together with the inclination of the surface of the card-flat foot 33.The middle of the press ram 12 preferably runs congruently with themiddle of this depression. The connecting line between the middle of thedepression and the middle of the press ram 12 corresponds at the sametime to the direction of linear movement of the press ram 12.

In the half, designated by L, of FIG. 5, there is no rib 11 present inthe version of the card-flat bar 21, as shown. As a replacement for theabsent rib 11, but with the same function, to be precise that ofavoiding an evasion of the press ram 12, a ram guide 15 is attached tothe ram 12 itself. The ram guide 15 is advanced together with the pressram 12. As a result, the insertion of the clothing strip 10 and of thecard-flat bar 21 is not impeded when the press rams 12 are in theirinitial position, as illustrated in FIG. 5. Owing to this measure, theapplication of the method does not depend on a type of construction ofthe card-flat bar which is specifically co-ordinated with it.

The press rams 12 may be moved by means of mutually independent lineardrives. The drive may be of the electrical, pneumatic or hydraulic typeof construction. A connection of the press rams 12 may also beenvisaged, for example by means of a linkage, in order to move bothpress rams 12 by means of the same drive. A mechanical drive actuated byhand may likewise be provided. If the holding-down device 13, too, isprovided with a drive, an automatic flow of the overall method may beenvisaged.

FIG. 6 shows a detail of the cross section of a revolving card flataccording to the invention from the right half, designated by R, of FIG.5 during the pressing operation, the press ram 12 being shown in theforemost position. The press ram 12 is pressed against the card-flatfoot 33 with the force F. On account of its elasticity, the front part16 of the press ram 12 which has penetrated into the depression betweenthe card-flat foot 33 and the rib 11 is deformed. The deformed part 16of the press ram 12 fills the entire depression, adapts to the contourand is partially upset. With the press ram 12 being adapted with itsfront part 16 to the contour of the depression by pressing with theforce F, the card-flat bars 31 can be manufactured with greatertolerance in terms of the shape of that side of the card-flat foot 33which lies opposite the clothing strip 10 and of the rib 11. Also, afterbeing used more than once, the card-flat bars 31 can be reused withoutany remachining of the faces and shapes against which the clip 35 bears.

The force F to be applied is to be co-ordinated with the selectedelasticity of the press ram 12, with the contour of the card-flat bar 31to be filled and with the clip 35 selected for fastening the clothingstrip 10.

Caption

-   1, 21, 31 Card-flat bar-   2, 22, 32 Web-   3, 23, 33 Card-flat foot-   4 Clothing-   5, 25, 35 Clip-   6 Prebending rollers-   7 Form rollers-   8 Holding device-   9 Foundation of the clothing-   10 Clothing strip-   11 Rib-   12 Press ram-   13 Holding-down device-   14 Receptacle-   15 Ram guide-   16 Deformation of press ram-   α Looping angle-   A First portion of the clip-   B Second portion of the clip-   C Third portion of the clip-   F Pressing force-   L Illustration of the card-flat bar 21 without the rib 11 according    to FIG. 2-   R Illustration of the card-flat bar 31 with the rib 11 according to    FIG. 3

1. Revolving card flat with a card-flat bar (21,31) which has acard-flat foot (23, 33) and a web (22, 32) lying above the card-flatfoot (23, 33), and with a flexible clothing in the form of a clothingstrip (10) and with at least one fastening element in the form of a clip(25, 35), the clip (25, 35) being attached with a first portion to theclothing strip (10), being led with a second portion along onelongitudinal side of the card-flat bar (21, 31) and partially loopingwith a third portion around the card-flat foot (23, 33) with a loopingangle (α), characterized in that the looping angle (α) amounts to lessthan 90° and to more than 30°. 2-12. (canceled)